Spray foam and mineral wool hybrid insulation system

ABSTRACT

A reduced thickness and/or reduced width insulation product is provided for use in combination with spray-on foam insulation. The insulation product is configured to be inserted into standard-size spaces between adjacent wall studs to which a spray-on foam insulation has been applied. The reduced size of the insulation product is specifically designed so that the combined width and thickness of the insulation product and the spray-on foam insulation fill the entirety of the building space, but do not overfill the space.

FIELD OF THE INVENTION

This invention relates building insulation products generally, and more particularly to a thermal insulation material for use in combination with spray foam thermal insulation for insulating wall spaces in residential and commercial buildings.

BACKGROUND OF THE INVENTION

Insulation products, such as fiberglass insulation, are widely accepted for residential and light commercial construction. The insulation products are made in a variety of configurations tailored to facilitate installation in specific locations. For example, in the United States, insulation batts or rolls are often installed in wall cavities between 2×4 or ×6 studs. In many applications, this insulation technique does not reach its optimal thermal performance due to air infiltration through the cladding, sheathing and into the insulation material.

One option to correct this problem is the use of a vapor-permeable water-resistant barrier, commonly referred to as “housewrap,” such as Tyvek® brand housewrap. While this material can help prevent air infiltration and control moisture, it can also be very costly.

Alternatively, a thin coating of a spray-on polyurethane coating can be applied to the inside surface of the exterior sheathing. This coating results in a spray-foam of from about ½-inch to 1½-inch thick. Using a closed-cell polyurethane foam effectively seals the exterior sheathing against all air infiltration. The foam also has a perm value of from about 0.5 to about 1.0, which almost eliminates the movement of water vapor through the wall. In addition to sealing, the closed-cell foam provides an increased R-value on the order of R-6.0 to R-6.5 per inch, as compared to the R-3.7 per inch typical of low-density fiberglass batts. After application of this thin foam coating, the remainder of the cavity is filled with a standard R-11/R-13/R-15 batt (for 2×4 studs) or an R-19/R-21 batt (for 2×6 studs).

The problem with this technique is that the presence of a foam layer within the wall space reduces the total space available for fitting the insulation blanket or batt. Insulation blankets and batts are normally manufactured so that their thickness is exactly the same as the distance between the exterior and interior wall sheathings, so as to maximize the thermal insulating potential of the space and to prevent bulging of the inner sheathing (e.g. wall board such as Sheetrock® brand wallboard) which could occur if the blanket/batt were thicker than the wall space. For insulation materials that are compressed for packaging and transport, the manufacture of the insulation rolls and batts is tightly controlled to ensure that their thickness recovers to exactly the design thickness on site. As a result, when a layer of spray-on foam is added to the inside surface of the exterior sheathing, the insulation blanket or batt must be forced into a space that is smaller than the space it was designed to fill. This can lead to a decrease in overall R-value of the insulation blanket or batt, and can also cause the interior walls to bulge between the studs, since the blanket/batt must be compressed in order to fit it completely within the wall space. Additionally, for homes in which the inner sheathing is glued onto the studs, this compression can cause the sheathing to separate from the studs, which can lead to bulging, cracking, etc. of the inner wall sheathing or of the joints between sheathing panels.

Accordingly, there is a need for insulation system that provides the combined benefits of spray-on foam and standard insulation blankets or batts, and which fully exploits the insulating properties of the blanket/batt, while preventing bulging or non-union of inner wall sheathing that can occur with current designs.

SUMMARY OF THE INVENTION

An insulation system for insulating a wall space is disclosed. The system can comprise a foam layer having a first thickness, and an insulation mat overlying the foam layer. The insulation mat can have a second thickness corresponding to an uncompressed condition of the insulation mat. The insulation mat and foam layer can be configured for installation within a space defined by a plurality of structure members, where the distance between first and second of the plurality of structure members is substantially equal to the sum of the first and second thicknesses.

A reduced size insulation product is disclosed comprising an insulation mat having a width and a thickness. The mat can be configured for installation between a plurality of structure members, where first and second of the plurality of structure members are separated by a space width, and third and fourth of the plurality of structure members are separated by a space thickness. The insulation mat thickness can be smaller than the space thickness by a first predetermined amount, the first predetermined amount corresponding to a thickness of foam insulation material disposed adjacent at least one of the plurality of structure members such that when the insulation mat is completely disposed between the plurality of structure members the insulation mat is substantially non-compressed.

A method of insulating a building space is disclosed. The method can comprise providing a first structural surface; applying a first insulation material to the first structural surface; applying a second insulation material over the first insulation material; and applying a second structural surface over the second insulation material to enclose the first and second insulation materials between the first and second structural surfaces without compressing the first or second insulation materials.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate preferred embodiments of the invention so far devised for the practical application of the principles thereof, and in which:

FIG. 1 is a partial perspective view of the insulation system of the present invention;

FIG. 2 is a top section view of the insulation system of FIG. 1;

FIG. 3 is a side view of the insulation system of FIG. 1;

FIG. 4 is a cross section view of an exemplary insulation mat for use in the insulation system of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

This invention is directed to insulation materials for use in insulating wall spaces of residential and commercial buildings. Insulation systems for use within the walls of buildings typically comprises a blanket or batt of thermal insulation material disposed between adjacent wall studs and between the inner and outer wall sheathing. Often, to improve insulative properties of the wall, a “house wrap” such as Tyvek® housewrap is installed on the outer surfaces of the outer wall sheathing to provide a barrier to wind entering the house through joints, seams or gaps in the house structure, as well as through permeable building materials used to construct the walls. Similar wind-resistance can be provided by a spray-on foam applied internal to the inner surface of the outer wall sheathing, and to the adjacent studs. This foam can provide multiple benefits, including increased insulative properties (inherent in the foam itself), decreased air permeability, and increased wall racking strength. One problem with using such foam with normally dimensioned thermal insulation rolls or batts is that the combined thickness of the foam and insulation material will inevitably be greater than the space between the inner and outer wall sheathing. Thus, the interior walls can be caused to bulge, impacting the aesthetics of the affected room.

In accordance with the Figures, and particularly FIGS. 1-3, there is shown an insulation system 10 for insulating a wall space in a typical residential or commercial building. The system 10 can comprise an insulation mat portion 20 and a spray-applied foam portion 30. The mat portion 20 and foam portion 30 are disposed between a pair of adjacent wall studs 40 a, b and between the inner and outer wall sheathings 50, 52 to insulate the wall space. The insulation mat and foam portions 20, 30 may have respective thicknesses “MT,” “FT” and the mat portion may also have a width “MW.”

In one embodiment, the foam portion 30 is a spray-applied foam, and is sprayed onto the exterior wall sheathing 52 to a desired thickness. The foam 30 is also applied to fill the seam between the wall studs 40 a, b and the exterior sheathing 52 to eliminate potential pathways for air infiltration. In an alternative embodiment, the foam portion 30 is applied to cover the inner surfaces of the wall studs 40 a, b to provide a U-shaped layer of foam within the wall cavity. Covering the wall studs with foam will provide increased structural stability to the wall (i.e. racking strength), as previously noted.

The insulation mat 20 may comprise a high or low density insulation material, formed from organic fibers such as polymeric fibers or inorganic fibers such as rotary glass fibers, textile glass fibers, stonewool (also known as rockwool) or a combination thereof. The insulation mat can comprise insulation boards, such as duct boards, insulation rolls or batts and acoustic insulation. Mineral fibers, such as glass, are preferred. Referring to FIG. 4, the insulation mat 20 can include first and second major surfaces 22, 24 and longitudinal side portions 23, 25. In some embodiments, a facing layer 27, which may be a cellulosic paper, typically formed from Kraft paper, coated with a bituminous adhesive material, such as asphalt, polymeric resin, or polymeric film, such as LDPE (low density polyethylene), or a combination of these materials, is provided on one major surface 22 of the mat portion 20. Other examples of facing layer 27 materials which can be bonded to the mat include (1) thin polymer films (PE (polyethylene), PA (polyamide)) and (2) FSK (foil-scrim-kraft). FSK is used mainly in commercial applications with more stringent fire safety requirements.

The insulation blanket or batt component 20 may include a pair of optional side tabs 28 and 29 that can be fastened to the wall studs 40 a, b, for example. Various known configurations for side tabs or flaps 28 and 29 are known. Alternatively, there may be no tabs on the Kraft facing. Further, the facing layer 27 may be water vapor impermeable or permeable, depending on the intended use.

In an exemplary embodiment, the mat portion 20 is a low density mat or batt formed from glass fibers bound together with a thermoplastic or thermosetting binder, such as nylon fibers, or heat cured binder, such as known resinous phenolic materials, like phenolformaldehyde resins or phenol urea formaldehyde (PUFA). Melamine formaldehyde, acrylic, polyester, urethane and furan binder may also be utilized in some embodiments. The insulation is typically compressed after manufacture and packaged, so as to minimize the volume of the product during storage and shipping and to make handling and installation of the insulation product easier. After the packaging is removed, the batt insulation product 20 tends to quickly recover to its prescribed thickness for insulation.

The foam component 30 can comprise any of a variety of spray-applied foam materials having either open and closed cell structures, and preferably, a spray-applied foam. Closed cell foams are preferred to open cell foams because they typically have a higher R value, they can provide a better barrier to air and moisture infiltration, and they are more resistant to absorbing moisture compared to open cell foams. Closed cell foams also are of higher density than open cell foams, and they can provide greater increases in the racking strength (described in more detail below) of the wall as compared to open cell foams. Furthermore, closed-cell foams provide good toughness, and the thickness at which they are applied is well controllable (i.e. they don't undergo extreme expansion when they are applied, and they can be applied to a specified thickness ±¼-inch).

Positioning the foam layer 30 between the exterior wall sheathing and the insulation mat 20 also prevents moisture from accumulating in the mat 20.

As noted, an additional benefit to providing a foam layer as described is that it can increase the “racking strength” of the wall structure, which is a measure of the strength of a wall when subjected to shear loading. The use of closed cell foam material in particular may improve racking strength of the wall sufficiently to allow the builder to utilize thinner stiffening materials in other areas of the wall structure, thus reducing overall material costs for the structure. For example, where current regulations require the use of thick plywood sheeting at the corners of the structure, using closed cell foam as previously described may enable the use of thinner plywood or other lower cost materials, such as foamboard, on the corners, reducing building costs.

Additionally, using closed cell foam can also allow the builder to forego installing expensive house wrap materials, such as Tyvek®, and may instead using standard building paper (e.g. kraft paper) for wrapping the house, or may forego wrapping the house entirely.

One preferred foam material is a closed-cell spray applied polyurethane foam insulation material manufactured and sold by ComfortFoam®, which is a division of Foam Enterprises, Inc., 13620-A Watertower Circle, Minneapolis, Minn. 55441-3787. This polyurethane foam can be supplied in a two-component form which is mixed at the work site and applied using a spray gun.

Although closed-cell foams are preferred, open-cell foams can also be used as appropriate. Open-cell foams are less resistant to air or wind infiltration and they generally have lower R values than closed-cell foams. As such, they may be appropriate for use in temperate climates, where lower R values are acceptable, and where a high degree of resistance to air and moisture infiltration is not required.

Foam materials other than polyurethanes can also be used, as appropriate. For example, thermoset foams such as polyisocyanurate, and phenolic can be applied in the wall cavity. Thermoset foams, requiring a resin and catalyst can be mixed onsite via spray mixing or liquid mixing and pouring. Thermoplastic foams such as polystyrene, polyethylene, and polypropylene can also be used. Thermoplastic foams, while generally impractical to foam in place, may be applied in either monolithic form or in particulate form bonded together by an adhesive. Furthermore, although the foam material has been disclosed as being a spray-applied material, pour-applied foam materials could also be used for the foam portion 30 of the invention. Additionally, foam layers or films, with, or without, adhesive backing layers, could be employed.

In one embodiment, the insulation mat portion 20 is a mineral wool insulation, and the foam portion 30 is a closed-cell polyurethane spray-applied material. In this embodiment, the thickness of the wall space may be about 3½ inches. Thus, the thickness of the foam portion 30 may be about ⅛-inch to about 2½-inches, preferably about 1-inch, and the thickness of the insulation mat portion 20 may be 3½ inches to about 1 inch, preferably about 2½ inches. Likewise, the width of the wall cavity may be about 14½ inches, such that the thickness of the foam portion 30 may be about ⅛-inch to about 1-inch, preferably about ½-inch on either side, and the width of the insulation mat portion 20 may be about 13½ inches. Thus, a 2½-inch insulation mat 20 may be rated at R-10, and the 1-inch foam portion 30 may be rated at R-6, resulting in a system insulation rating of about R-16. This is substantially greater than the insulation rating obtainable where a 3½ inch thickness of insulation material alone is used to fill the space. It is noted that the actual insulation rating of the system will be slightly greater than R-16 if the studs are coated with a ½-inch layer of foam 30 because this ½-inch thickness will run the entire thickness of the wall space, providing ½-inch thick slices of R-6 material running along each side of the mat 20.

It is noted that the foam and insulation materials can be provided in any desired width and thickness FT, MT, MW, as long as the combination of the respective dimensions is substantially equal to the width and thickness of the wall cavity to be insulated. The proportional thickness between foam and insulation batt/roll can also be varied, depending on the desired thermal performance and installed cost targets for the system. In practical application, the insulation mat portion 20 will be provided with external markings on the facing layer 17 that indicate the appropriate thickness of foam 30 to be applied to the wall cavity, and whether the foam should be applied to both the external sheathing 52 and studs 40 a, b, or to the external sheathing 52 alone. The indicated thicknesses will correspond to the reduced thickness (and optionally width) of the insulation mat 20 to which the markings are applied. Thus, the foam thickness FT can be from about ½-inch to about 1½-inch, depending on the associated mat thickness MT and the dimensions of the wall space.

In addition to the above mentioned advantages, using the disclosed arrangement provides the additional benefit of preventing waste by optimizing the insulative properties of each component in the system 10. With prior techniques, a 1-inch thick layer of foam insulation would typically be applied within a wall space having a 3½ inch clearance between the interior and exterior sheathing 50, 52. A 3 1/2 inch thick insulation mat would then be forced into the wall space, compressing the mat by about 1-inch in thickness to conform it to the available space. As a result, a portion of the R-value of the insulation mat would be wasted (e.g. under a 1-inch compression an R-13 mat would be reduced to about R-11). This waste would also occur where foam material is applied to the studs, thus requiring a typically sized batt to be compressed laterally in order to fit it into the wall space. As previously noted, compressing the mat also results in an increased likelihood for bulging of the interior wall sheathing or non-union of the sheathing with the wall studs (where the sheathing is glued to the studs). With the inventive system, such waste, bulging and non-union is eliminated.

It is expected that the insulation system 10 will be sold as a multi-component system having an insulation mat portion 20 and a spray-applied foam portion 30. The insulation mat portion 20 will be labeled with the R-value of the ultimate mat/foam combination, and will also specify the appropriate type and thickness of foam 30 to be applied to the wall space. This, in combination with the reduced thickness (and optionally the reduced width) of the mat 20 is expected to minimize the chance that the installer could use the mat 20 in an unintended manner (i.e. without the foam).

In use, the installer can unpack the insulation mat 20 component from its package and allow it to decompress or “recover” to its design thickness. The wall space, comprising the exposed surfaces of the exterior wall sheathing 52 and wall studs 40 a, b can be prepared by removing construction debris or loose dirt (note that this preparation step may not be required, since spray foam is expected to adhere well to the wall space even if debris or dirt are present), etc., followed by the spray application of a layer of closed-cell polyurethane foam 30 to the inner surfaces of the wall sheathing 52, and depending on the dimensions of the insulation mat 20, to the inner surfaces of the wall studs 40 a, b. The foam 30 should be allowed to cure thoroughly, whereupon the mat 20 may be cut to length and fit within the wall space, snugging it up against the foam layer 30.

Although it is preferred that the foam be allowed to cure prior to the application of the insulation mat, it is also possible to engage the mat 20 with the foam layer 30 while the foam is still wet. This may be advantageous because it adheres the mat to the foam, thus ensuring that there will be no gaps between the two. Such adherence may not be necessary with the present invention, however, because the close and careful dimensioning of the foam layer 30 and the mat 20 will ensure continued long term contact between the two without substantial air gaps. Furthermore, allowing the foam to dry thoroughly prior to application of the mat 20 is preferable to a “wet foam” fit-up method because it ensures proper curing of the foam.

As previously noted, closed cell foams can be applied to fairly close tolerances due to the fact that they do not undergo substantial expansion upon application. However, if too great a thickness of foam is applied, the foam can be shaved to reduce the thickness to the appropriate amount. This can be done rather easily if the shaving or trimming is performed within about an hour after spraying. Greater difficulty in shaping the foam will be encountered, however, if the foam is allowed to cure for several hours first, due to substantial hardening of the foam as it cures.

Accordingly, it should be understood that the embodiments disclosed herein are merely illustrative of the principles of the invention. Various other modifications may be made by those skilled in the art which will embody the principles of the invention and fall within the spirit and the scope thereof. 

1. An insulation system for insulating a wall space, comprising: a foam layer having a first thickness; and an insulation mat overlying the foam layer, the insulation mat having a second thickness corresponding to an uncompressed condition of the insulation mat; wherein the insulation mat and foam layer are configured for installation within a space defined by a plurality of structure members, the distance between first and second of the plurality of structure members being substantially equal to the sum of the first and second thicknesses.
 2. The insulation system of claim 1, wherein the first and second structure members comprise internal and external wall sheathing, respectively, the foam layer is positioned against the external wall sheathing and the insulation mat is positioned against the internal wall sheathing.
 3. The insulation system of claim 2, wherein the insulation mat further comprises a width substantially equal to a distance between third and fourth of the plurality of structure members.
 4. The insulation system of claim 2, wherein the insulation mat further comprises a width that is smaller than a distance between third and fourth of the plurality of structure members by a predetermined amount, the predetermined amount being substantially equal to a thickness of foam positioned between the insulation mat and the third and fourth structure members.
 5. The insulation system of claim 4, wherein the third and fourth structure members comprises wall studs.
 6. The insulation system of claim 1, wherein the foam comprises polyurethane spray-applied foam.
 7. The insulation system of claim 6, wherein the foam comprises a closed-cell foam.
 8. The insulation system of claim 6, wherein the foam comprises an open-cell foam.
 9. The insulation system of claim 1, wherein the first thickness is from about 0.5-inch to about 1.5-inches.
 10. The insulation system of claim 9, wherein the second thickness is from about 2-inches to about 3-inches, and the combination of the first and second thicknesses is about 3.5 inches.
 11. A reduced size insulation product comprising: an insulation mat having a width and a thickness, the mat configured for installation between a plurality of structure members, first and second of the plurality of structure members being separated by a space width, and third and fourth of the plurality of structure members being separated by a space thickness; wherein the insulation mat thickness is smaller than the space thickness by a first predetermined amount, the first predetermined amount corresponding to a thickness of foam insulation material disposed adjacent at least one of the plurality of structure members such that when the insulation mat is completely disposed between the plurality of structure members the insulation mat is substantially non-compressed.
 12. The reduced size insulation product of claim 11, wherein the width of the insulation mat is smaller than the space width by a second predetermined amount, the second predetermined amount corresponding to a thickness of foam insulation material disposed adjacent at least one of the plurality of structure members.
 13. The reduced size insulation product of claim 11, wherein the first and second structure members comprise wall studs, the third structure member comprises an external sheathing layer, and the fourth structure member comprises a wall board layer.
 14. The reduced size insulation product of claim 11, wherein the foam insulation material comprises polyurethane spray-on foam disposed adjacent the first, second and third structural members.
 15. The reduced size insulation product of claim 11, wherein the foam insulation material is an open cell foam.
 16. The reduced size insulation product of claim 11, wherein the foam insulation material is a closed cell foam.
 17. The reduced size insulation product of claim 11, wherein the foam insulation material thickness is about 0.5 inch to about 1.5 inches.
 18. The reduced size insulation product of claim 17, wherein a combined thickness of the foam insulation material and the insulation mat is about 3.5 inches.
 19. The reduced size insulation product of claim 11, wherein the space width is about 14.5 inches, the space thickness is about 3.5 inches, the foam insulation material thickness is about 1 inch and the batt thickness is about 2.5 inches.
 20. An insulation system comprising: a foam layer having a foam thickness; and an insulation mat having a width and a thickness, wherein the foam layer and the insulation mat are configured for installation within a wall space defined by oppositely disposed internal and external wall sheathing members and oppositely disposed wall stud members, the space having a width defined between the sheathing members and a thickness defined between the wall stud members; wherein the thickness of the insulation mat is smaller than the space thickness by a predetermined amount, the predetermined amount being substantially equal to the thickness of the foam layer.
 21. The insulation system of claim 20, wherein the width of the insulation mat is smaller than the space width by a predetermined amount, the predetermined amount being substantially equal to a second thickness of the foam layer disposed between the insulation mat and each of the wall stud members.
 22. The insulation system of claim 20, wherein the foam layer comprises a spray-applied polyurethane foam material.
 23. The insulation system of claim 22, wherein the spray-applied polyurethane foam material is an open-cell foam or a closed-cell foam.
 24. The insulation system of claim 20, wherein the foam layer thickness is about 0.5 inch to about 1.5 inches.
 25. The insulation system of claim 24, wherein a combined thickness of the foam layer and the insulation mat is about 3.5 inches.
 26. The insulation system of claim 20, wherein the space width is about 14.5 inches, the space thickness is about 3.5 inches, the foam insulation material thickness is about 1 inch and the insulation mat thickness is about 2.5 inches.
 27. A method of insulating a building space comprising: providing a first structural surface; applying a first insulation material to the first structural surface; applying a second insulation material over the first insulation material; and applying a second structural surface over the second insulation material to enclose the first and second insulation materials between the first and second structural surfaces without compressing the first or second insulation materials.
 28. The method of claim 27, wherein the first structural surface comprises exterior wall sheathing, the second structural surface comprises interior wall sheathing, the first insulation material comprises a foam material, and the second insulation material comprises an insulation mat.
 29. The method of claim 27, wherein the step of providing a first structural surface further comprises providing third and fourth structural surfaces at opposite ends of the first structural surface to create a structural space having an inner surface, and wherein the step of applying the first insulation material comprises spraying a foam insulation material onto at least a portion of the interior surface to an applied foam layer thickness of from about 0.5 inches to about 1.5 inches.
 30. The method of claim 29, wherein the structural space has a width defined by the distance between the third and fourth structural surfaces, and a space thickness defined by the distance between the first and second structural surfaces, and wherein the combined widths and thicknesses of the first and second insulation materials is substantially equal to the space width and thickness.
 30. The method of claim 30, wherein the space width is about 14.5 inches, the space thickness is about 3.5 inches, the step of applying the first insulation material comprises spraying the foam insulation material onto the entire interior surface to an applied foam layer thickness of about 1.0 inches, and the step of applying the second insulation material comprises applying an insulation mat having an uncompressed thickness of about 2.5 inches and a width of about 12.5 inches.
 31. The method of claim 30, wherein the foam insulation material comprises a closed-cell polyurethane foam material
 32. The method of claim 30, wherein the second insulation material comprises mineral wool. 